1. Field of the Invention
The present invention relates to a light source module, and more particularly, to a light emitting diode (LED) light source module.
2. Descriptions of the Related Art
Common projection systems currently available typically use xenon bulbs or ultrahigh-pressure mercury lamps as a light source. However, such projection systems must be provided with a high-voltage power supply circuit and a superior cooling system in conjunction with the xenon bulbs or ultrahigh-pressure mercury lamps. Furthermore, the xenon bulbs and ultrahigh-pressure mercury lamps have disadvantages, such as a short service life, high prices or uneven light intensity distribution. In contrast, light emitting diodes (LEDs) are free from such disadvantages and, therefore, have become a preferable choice for replacing the xenon bulbs and ultrahigh-pressure mercury lamps.
FIG. 1 schematically illustrates a conventional projection device 1 that uses LEDs as a light source. The conventional projection device 1 comprises an imaging module 11 and an LED light source module 12 including a plurality of LED modules 13. The LED modules 13 may be red, green and blue LED module respectively. Because LED modules 13 of different colors do not require the use of an additional color splitting device such as a color wheel, the LED light source module 12 per se can provide the three primary colors to the imaging module 11. Because of the reduced complexity in system design and the reduced cost, great importance has been attached to the development of projection devices that uses LEDs as a light source. Furthermore, as LEDs feature a quick start process, the LED modules 13 may be controlled by a control module to be switched on and off alternately or simultaneously at a high frequency. In this way, the luminance of the individual LED modules 13 can be controlled and the heat concentration caused by the continuous operation of the LED modules 13 be avoided, which would otherwise reduce the light emission efficiency and service life of the LED modules.
Compared to the conventional light sources, the past LED modules still have drawbacks in terms of luminance intensity, so their use in projection devices is greatly restricted. With the continuous development of high current/high power LEDs, the luminance intensity thereof has gradually come to meet the requirements of more applications. Unfortunately, when applied to the structure of the aforesaid LED light source module 12, high current/high power LED modules may experience vibration due to the electromagnetic forces induced by high voltage or high current when switched at a high frequency, resulting in intolerable large noises.
No solutions have been proposed yet to suppress the noises of the LED light source module 12, so although high power LEDs are gradually finding a wide application in projection devices, the users' desires to use such projection devices are compromised due to the overloud noises. Therefore, it is important to provide an LED light source module with high power but low noise for use in a projection device.